265 hemi straight six

The 265 Hemi 6's weren't really true Hemi's.

Engineering and design features[edit]
The Hemi-6 is a pushrod O.H.V. (overhead valve) engine, with combustion chambers comprising about 35% of the top of the globe. This creates what is known as a low hemispherical shaped chamber. Although the Hemi-6 does not contain truly hemispherical combustion chambers, the "Hemi" moniker was used primarily for its marketing cachet based on the reputation of Chrysler's 1950s-1970s (true) Hemi V8 engines.

The Hemi-6 valves are 18 degrees (included angle) along the crankshaft axis opposed valves, with intake valves as large as 1.96". The 6 intake and 6 exhaust valves open toward each other, and into the center of the combustion chamber. In addition, both valves are slightly inclined across the crankshaft axis (similar to a conventional "wedge" chamber). The cylinder head is a non-crossflow design, meaning the 6 intake and 6 exhaust ports are on the same (left, Australian and British passenger's side) of the engine.

Unlike Chrysler's contemporaneous hemi V8 engines, the Hemi-6's rocker arms are mounted on individual studs (similar to the Chevrolet "big block" V8), rather than on 2 separate rocker shafts as in all 1951-58 Hemis—Dodge, DeSoto, Imperial, and Chrysler "Firepower" and 1964-'71 426 V8s.

All Hemi-6s share a robust crankshaft supported by seven main bearings, and this family of engines quickly developed a reputation for excellent performance, economy, and durability.

The Australian Hemi engines were designed by a five-man team which included the late Maurice Harcus.